Legion

Legion, principal unit of the Roman army, having between 3,000 and 6,000 infantry with attached cavalry. By the 1st century B.C. the cohort, composed of 6 companies, was the tactical unit. There were 10 cohorts to a legion. The leader of a legion was a legate or a consul. Soldiers of the Roman Empire were recruited to a legion for a term of 20 to 25 years.